This change introduced an MSAN error https://bugs.llvm.org/show_bug.cgi?id=50112

Rebased. Now using native cxxBaseSpecifier and hasDirectBase.

In D69218#2667523, @steveire wrote:

What name/email should I use for the commit?

In D69218#2654614, @steveire wrote:

@nick Sorry that getting these changes merged takes so long.

@njames93 If you have an alternative way forward, please let us know what it is.

Otherwise, this LGTM too and we should merge it soon unless there are objections which haven't been addressed.

Is this hack actually needed? I could not reproduce a problem with https://bugs.chromium.org/p/chromium/issues/detail?id=860398#c13 repro, the breakpoint fires for me and I see the variable.

In D99107#2642451, @rnk wrote:

We try to uphold the invariant that -g flags do not affect generated code, so I don't think we should do this.

Could you please commit the patch for me? I do not have commit rights.

Lint fixes

Forgot to remove a duplicated test

Rebased. Removed things reimplemented and landed in D81552 + D79063.

FYI: this breaks some msvc compatibility

template <class> class X {};
template X<int>;

Thanks @zequanwu, much appreciated.

We didn't see it in the code bases I work with, so is boost a special case, or an example of a common practice?

I feel like doing interprocedural analysis for this is overkill. What is the benefit of boost::ignore_unused(foo); rather than the more common (void) foo;? Any examples?

This warning can be turned off by the flag -Wno-uninitialized-const-reference.

This diagnostic bring headaches because frequently -Wunused-variable suppression is done via no-op pseudo-consuming function like [boost::ignore_unused](https://www.boost.org/doc/libs/1_73_0/libs/core/doc/html/core/ignore_unused.html). Particularly, it fires in Boost here https://github.com/boostorg/concept_check/blob/e69c81326d5a4359ac53f9c6fe53fc2baf24df50/include/boost/concept_check.hpp#L135-L141.
Is it possible to make the diagnostic not fire for empty body consuming functions?

No, I do not have commit rights.

I cannot be a reviewer, just added some dummies questions. And, @spatel, thanks for working on this!

Fixed typo.

Regenerated the docs, added more tests.

Addressed comments.